Otitis media (OM) is very common, especially in children. OM often begins with a viral infection of the upper respiratory tract that alters the micro-environment of the upper respiratory tract, Eustachian tube, and middle ear such that bacteria resident in the nasopharynx invade and populate the middle ear. This invasion can inflame and block the Eustachian tube, interfering with middle ear ventilation, pressure equilibration, and drainage. Fluids accumulate and pressure increases in the normally air-filled middle ear space, causing great pain. In severe cases of OM, sound perception structures can be damaged. Persistent or recurrent OM may be caused by bacteria that emerge from dormancy in the middle ear, having been shielded from antibiotics by a slimy biofilm.
OM currently is treated using antibiotics and/or by inserting a tympanostomy tube through a surgical incision in the tympanic membrane so as to drain and depressurize the middle ear space. The efficacy of antibiotic treatment is limited by the route of delivery. Antibiotics can be delivered systemically, but a high dose often is required to attain therapeutic levels (i.e., above minimum inhibitory concentration) in the middle ear, and such levels often are attained after a significant lag time. Antibiotics also can be delivered by lavage, or via drops into the ear canal. Such delivery routes can be difficult to control, and often are not effective to achieve prolonged therapeutic levels of antibiotic in the middle ear. Antibiotics also can be delivered by injection into the middle ear, or by inserting antibiotic-impregnated materials into the middle ear, but such methods involve piercing or cutting the tympanic membrane, which requires general anesthesia and can damage the tympanic membrane. Surgical insertion of tympanostomy tubes also carries risks, including tympanoclerosis (i.e., scarring of the tympanic membrane), hearing loss, persistent otorrhea (i.e., discharge of pus from the tube) and infection.
The National Institute on Deafness and Other Communication Disorders (NIDCD), a part of the National Institutes of Health, recently launched a $2,000,000 funding initiative to support the development of alternative strategies and new approaches for preventing and treating OM. In its request for applications (RFA-DC-02-002), NIDCD stated that: (1) OM causes significant childhood morbidity and is increasingly affecting general public health; (2) OM is the leading reason for Emergency Room visits; (3) OM is the second leading reason for doctors' office visits; (4) OM is the leading reason of childhood antibiotics prescriptions, accounting for more than 40% of all outpatient antibiotic prescriptions; (5) OM is the leading reason for childhood hearing loss; and (6) OM is the leading reason for general anesthesia in children. In addition, NIDCD blamed the use of broad-spectrum antibiotics to treat OM for the alarming emergence of multiple antibiotic resistant bacteria in three of the genera that can cause OM (Streptococcus pneumoniae, non-typeable Haemophilus influenzae, and Moraxella catarrhalis). As a consequence, many first and second line antibiotics are becoming less and less effective against OM and other diseases, including pneumonia and meningitis. NIDCD concluded that “the development of novel approaches for the study, treatment and prevention of OM is urgently needed to: 1) reduce OM morbidity and the associated costs; and 2) preserve the efficacy of antibiotics used for the treatment of OM and other common serious diseases.”